import * as React from 'react'; import Document, { Html, Head, Main, NextScript } from 'next/document'; import createEmotionServer from '@emotion/server/create-instance'; import theme from '../src/theme'; import createEmotionCache from '../src/createEmotionCache'; export default class MyDocument extends Document { render() { return ( {/* PWA primary color */} {/* Inject MUI styles first to match with the prepend: true configuration. */} {this.props.emotionStyleTags}
); } } // `getInitialProps` belongs to `_document` (instead of `_app`), // it's compatible with static-site generation (SSG). MyDocument.getInitialProps = async (ctx) => { // Resolution order // // On the server: // 1. app.getInitialProps // 2. page.getInitialProps // 3. document.getInitialProps // 4. app.render // 5. page.render // 6. document.render // // On the server with error: // 1. document.getInitialProps // 2. app.render // 3. page.render // 4. document.render // // On the client // 1. app.getInitialProps // 2. page.getInitialProps // 3. app.render // 4. page.render const originalRenderPage = ctx.renderPage; // You can consider sharing the same Emotion cache between all the SSR requests to speed up performance. // However, be aware that it can have global side effects. const cache = createEmotionCache(); const { extractCriticalToChunks } = createEmotionServer(cache); ctx.renderPage = () => originalRenderPage({ enhanceApp: (App) => function EnhanceApp(props) { return ; }, }); const initialProps = await Document.getInitialProps(ctx); // This is important. It prevents Emotion to render invalid HTML. // See https://github.com/mui/material-ui/issues/26561#issuecomment-855286153 const emotionStyles = extractCriticalToChunks(initialProps.html); const emotionStyleTags = emotionStyles.styles.map((style) => (